Deaths in Custody and Police Shootings in Texas

[circushaase]

For my Capstone project for my Data Sci bootcamp, I'm using the dataset published by the Texas Justice Initiative on deaths in police custody in Texas from 2005-2016 and I could use some help. Specifically, right now I'm looking for some statistics to compare the data to. Texasjusticeinitiative.org compared the death rates to Texas population rates, but I would like to compare to population rates of all people in custody during that time, in order to control for the fact that people of minority ethnicities are disproportionately arrested, to see beyond that if it is also more deadly for people of certain ethnicities to be in custody.
These seem like tricky numbers to find, but if you have any recommendations, I am definitely open to them.
I also have another data set collected by VICE on officer related shootings. This set only has statistics for Houston, Dallas/FtWorth, San Antonio and Austin.

Here's my project in its current progress:
https://github.com/circushaase/Capstone2